Cooling arrangements for internal combustion engines



April 9; 1935. F. GossLAu l-:r AL 1,997,173

COOLING ARRANGEMENTS FOR INTERNAL COIBUSTI-'N ENGINES Filed Aug. 2, 19325 Sheets-Sheet 1 .mumllllllllllll April 9, .1935. 4 F GQSSLAU Er AL1,997,173,

COOLING ARRANGEMENTS FOR INTERNAL COMBUSTION ENGINES 3 Sheets-Shet 2Filed Aug. 2, 1932 I l l l I I L April 9, 1935 F. GossLAu r-:r Ax.1,997,173

COOLING ARRANGEMENTS-FOR INTERNAL COMBUSTION ENGINES Filed Aug. 2, 19325 Sheets-Sheet 3 Patented Apr. v9, 1935 UNITED STATES COOLINGARRANGEMENTS FB INTERNAL COMBUSTION ENGINES Fritz Gosslau,Berlin-Charlottenburg, and Johannes Lusznat, Berlin-Haselhorst, Germany,

assignors to Siemens schaft, Siemensstadt,

& Halske, Aktiengesellnear Berlin, Germany, a

corporation of Germany Application August 2, In Germany 1o claims.

Our invention relates to improvements in cooling arrangements forinternal combustion engines, and more particularly to a coolingarrangement for reducing the power required for air cooling radiallystationary cylinder-aeroengines.

In the competition between air-cooled and water-cooled internalcombustion engines, the air-cooled engine is often considered as beingdisadvantageous owing to the great air resistance brought about by thecylinders. While only the radiator of liquid-cooled engines is exposedto the strong current of air during the night, and absorbs in the mostfavorable caseabout 7 per cent of the propeller power, it has not beenpos- `sible to obtain for air-cooled engines such a low value of thepower required for cooling purposes, in spite of the numerousimprovements hitherto made. Corresponding conditions are also present instationary internal combustion engines.

'I'he object of our invention is to provide a cooling arrangementwhereby the power necessary for air cooling internal combustion enginesis reduced even below the valueof that necessary .for coolingwater-cooled engines.

The invention is based on the fact, that diil'erence in temperaturebetween an air-cooled 4 cylinder and the cooling air ismateriallygreater change between the cylinder-walls and the liquid inthe latter type'of engine`as compared with the much more eilicient heatexchange between the radiating elements of an air-cooled cylinderdirectly with the cooling air. Numerically the average temperature of anair-cooled cylinder may be estimated at 180 C., and that of the liquidin the radiator in the most favorable case (when using ethylene glycol)at 120 C.

Besides, in a liquid-cooled cylinder very large 'amounts of liquid mustbe circulated in order to avoid overheating the hottest parts of thecylinder, for instance the head, amounts which are much too large forthe normally cooler cylinder portions to which they are incidentallysupplied, and which therefore constitute a waste of circulating energy.

By properly designing the radialdimensions of the cooling iins and by asufcient supply of cooling medium to be circulated around the coolingtins, it is possible to carryy off the heat in air-cooled cylinders inaccordance with the temperature prevailing at the different-pointsthereof. According to the invention this may be ac- 1932, Serial No.627,248 August 8, 1931 opening of a substantially conical cooling jacketenclosing the cooling ilns of decreasing crosssection in such a manneras to permit at the cylinder head the passage of agreater amount ofcooling air than at the lower end thereof.

Our invention is illustrated in the accompanying drawings forming partof this application in which Fig. 1 is a front elevational View of aninternal combustion engine cylinder embodying our invention.

Fig. 2 is a central vertical section through Fig. l, including a curveshowing relatively thetemperature conditions prevailing in differenthorizontal sections of the cylinder.

Fig. 3 isa side elevation of Fig. 1.

Fig. 4 is a sectional plan view showing a modified form of theair-cooling jacket of Fig. 1.

Fig. 5is a central vertical section-in larger scale throughan enginecylinder showing another embodiment of the invention including a cowlarranged over the cylinder and chambers for the supply and discharge ofthe cooling air.

Fig. 6 is a central vertical section at right angles to the section ofFig. 5.

Fig. 7 is a rear elevation of the cylinder shown in Fig. 5, partly insection taken on the line E-F of Fig. 8.

Fig. 8 is a sectional plan view taken on the line Fig. 9v is a top view,partly in section. taken on the line C-D of Fig. 5.

Referring tov Fig. 1, the cylinder I Ais provided with circular coolingfins 2, the radial dimensions of which decrease from the cylinder headtoward the ange 3, the cooling iins being enclosed in an approximatelyconical air-cooled jacket 4. Across the cylinder head extend thevertical cooling ribs 5. The cooling -jacket has a substantiallyV-shaped inlet opening 6 extending longitudinally along the cylinder andhaving its apex near the flange 3..

The form of the inlet opening 6 is carried out in accordance with thetemperatures prevailing in the cylinder, the dotted curve 1 indicated inFig. 2 showing the temperature conditions of the different sections ofthe cylinder. 'I'his curve is obtained by plotting a radially outwardlyfrom the inner cylinder surface the prevailing temperature values't ofthe appertaining cylinder wall portions. The values t are also indicatedin dotted lines in Fig. 2. The cooling air inlet opening 6 vis enlargedat the cylinder lhead into a rectangular i'orm so as to expose all ofthe vertical cooling fins extending across the head. In this mannerI anoverheatcomplished by dimensioning the inlet or outlet ing at thecylinder headis prevented, since a greater amount of cooling air flowinginto the.

of the cylinder opposite to inlet opening I, aA

discharge duct 9 (Fig. 3) is so arrangedv as not to cause a whirling ofdischarged cooling air with outside atmosphere.

The supply of diierent quantities of cooling air to the cylinder neednot necessarily be determined at the front ,portion of the cylinderfacing the direction of travel, but may be effected by suitable designsat the rear portion thereof, for instance at the discharge side I5 asshown in the embodi ment Fig. 4. The direction of night is indicated bythe arrow I0. The streamline body II serves to direct the air and toenclose the cylinder. The cooling air by reason of the dynamic pressurecaused by the movement of the body II passes through the passage I2 andflows horizontally. around the cylinder through the ducts formed by thehorizontal ribs I4 and-the cylinder body I3. fIo increase the suctioneifectin the passage I2 a blower I6 is provided. The arrangement and theradial dimensions of the ribs correspond to the embodiment shown inFigs. 1 and 2. Also in this case an effective cooling is brought about'by the supply of dierent amounts of the cooling medium to the diiierentportions of the cylinder. Buch an arrangement is particularly ofadvantage in cases in which a suiicient supply of cooling air at thefront portion of the cylinder encounters diiliculties.

In the above described arrangement the height of the cooling finsdecreases in a known'manner from the head of the cylinder toward theflange, 4o but according to the invention only so much cooling air issupplied to the individual strata extending at right angles to thecylinder axis as is required to carry off the heat developed in eachindividual cylinder stratum. In the embodiment shown in Fig. 5, thecylinder I surrounded by the above described conical air cooling jacketis provided with a streamline cowl 20 and has a separate head II. The'scavenging and charging air is supplied to the cylinder so I through thepassage I8 and the port 23, the

exhaust gases being discharged through the port 3l and the passage I9.The cooling air supplied by a blower passes through the passage 2l andis distributed in the'space 22 behind the cylinder 5,7l in the yingdirection, formed by the streamline cowl 20, thence it passes throughthe opening 6 (similar to that shown at 6 in Fig. 1) and is'tieilectediaround'the sides=''of the cylinder I,-and

enters through the oppositely disposed opening 9 e the space 23 formedin -frontof the cylinder I by a streamline cowl. The hot cooling air isthen discharged at 24.

As will be seen froni Fig'. 7, the width of the inlet opening for theingress of the coolingl e5 medium to be circulated around the cylinderincreases from the top of the scavenging and charging duct I8 toward thehottest point of the cylinder near the top and then decreases at itsupper portion. The width of the opening 5 bellow duct Il is stillnarrower than above it. since at this point the cylinder is relativelythe coolest. The amount of cooling air flowing through -the inletopening 6 corresponds, therefore, to the quantity required for coolingthe different sections of the cylinder exposed to heat. thus ensuring acooling of the cylinder at all points with the smallest possible amountof cooling air in a most eective manner. A particularly advantageousform of construction is obtained by combining the cooling air passages,the passages for the supply of the scavenging and charging air as wellas the passages for the discharge of the combustion gases to a singlebody as is dis# closed in Figs. 5, 8 and 9. In order to easily combinethis bocht with the cylinder, it is divided into two sections along alongitudinally directed plane along the cylinder axis and at rightangles to the general direction of the flow of the. cooling air arolmdthe cylinder iins, as shown in Figs. 8 and 9. One section located to therear of the cylinder contains the supply chambers and the ports for thecooling air and the scavenging air, the front section contains theexhaust ports and discharge chambers for the cooling air and the exhaustgases. The two sections are held togetherby the screws arranged at thelevel of passage Il for the scavenging air and at the level of passageI9 lfor the exhaust gases thus attaining at the same time a reliableAjoint for these passages. A further screw 26 cooperating with ashoulder 21 of the streamline cowl 20 is arranged above thecylinderhead. The space between the cylinder head and the cowl is so designed asto enclose the elements required for the operation of the engine andwhich are arranged on the cylinder head, such as fuel nozzle 28, sparkplug 29 and compressed air starting inlet '2l so that these elements donot bring about any" resistance to flight in the case of the cylinderprojecting into the atmosphere. These elements are, however, accessiblethrough covers Il held in position by means of the springs 32. As willbe seen from Fig. 9 the cooling air. streaming over the cylinder headjis directed through the ducts between the cooling fins which are sodesigned formed between the inlet port and the exhaust port as to obtainas far as possiblepaths of equal length for the cooling air. In thismanner a uniform'cooling of the cylinder head is ensured. The numeral inFig. 5 denotes a portion of the supporting or wing surface of4 anaeroplane.

Our invention renders also possible a remarkable improvement forstationary air-cooled engines, since it eliminates a waste of coolingair in the neighborhood of the flange. In vehicles and in streamlinebodies the power required for cooling purposes may/be stillfurtherreduced according to the invention when employing the above describedmeans at the inlet yopening of `the blower, by utilizing the dynamicpressure caused by the movement of the craft and by choosing suitabledimensionswf crosssection so as to prevent a whirling of the dischargedcooling air with outside atmo'sphere. v

Further improvements which also reduce the power required for coolingpurposes lie in the choice of an. air cooling blower of high emciency,for instance, of an axial blower with blades of wing-like cross-section.

We claim as our invention:

1. In an air cooling arrangement for internal combustion enginecylinders, the combination with an engine cylinder of a pluralityof-annular cooling fins spaced around the cylinder wall, and dimensioned4in relative height proportional to the relative amounts of heatdeveloped in the different cylinder portions adjacent' to the severaliins, means for supplying cooling air to said cylinder, and meanstor'directing said air between said ilns` transversely to the cylinderaxis vand distributing it in individual amounts among said iinsproportional to the relative amount of heat radiated by each iin.

2. In an air cooling arrangement for internal combustion enginecylinders, the combination with an engine cylinder or a plurality ofannular cooling ns spaced around the cylinder wall, anddimensioned inrelative height proportional to the relative amounts of heat developedin the dillerent cylinder portions adjacent to the several ns, means forsupplying cooling air to said cylinder, and a jacket surrounding saidvfins to form ducts with said fins, said jacket having axially extendingair ports on diametrically opposite cylinder sides, the conilguratlonand area of one of 'said ports being dimensioned so as to permit at thehotter cylinder portions correspondingly-.larger amounts of air to entersaid ducts than at the cooler cylinder portions.

3. In an air cooling arrangement for internal combustion lenginecylinders, the combination with an engine cylinder oi a plurality ofannular cooling llns spaced around the cylinder wall, and dimensioned inrelative height proportional to the lrelative amounts of heat developedin the -diei'ent cylinder portions adjacent to the several iins, meansfor supplying cooling air to said cylinder, and a jacket surroundingsaid fins to form ducts with said fins, said jacket having axiallyextending air ports on diametrically opposite cylinder sides, one ofsaid ports being V- shaped, having its wider portion near the cylinderhead, so as to permit correspondingly' larger amounts of air to enterthe ducts at the hotter cylinder portions than at the cooler portions.

4. In an air cooling arrangement for internal` combustion enginecylinders, the combination' with an engine cylinder of a plurality ofannular cooling fins spaced around the cylinder wall, and dimensioned inrelative height proportional to the relative amounts of heat developedin the different cylinder portions adjacent to the several lns, meansfor supplying cooling air to said. cylinder, and a jacket surroundingsaid fins to form ducts with said ilns, said jacket having axiallyextending air ports on diametrically opposite cylinder sides, one ofsaid ports being vshaped, having-its wider portion near the cylinderhead and being enlarged at the head into of rectangular shape, so as topermit correspondingly larger amounts of air to enter the ducts at thehotter cylinder portionsthan at the cooler portions.

5. In an air cooling arrangement for internal combustion enginecylinders, the combination with an engine cylinder of a plurality ofannular cooling fins spaced around the cylinder wall, and transversecooling fins spaced across the cylinder head and extending in the ilowdirection of the cooling air to be supplied, all of said tins beingdimensioned in relative height proportional to the relative amounts ofheat developed in the different cylinder portions adjacent to theseveral lns, means for supplying cooling air to said cylinder and ajacket surrounding said ilns to form ducts with saidtins, said jackethaving axially extending air ports on diametrically opposite cylindervsides, one oi said ports being v-shaped, having its wider portion nearthe cylinder head and being enlarged opposite the cylinder head into asubstantially rectangular shape, whereby larger amounts of air areindividually permitted to pass between the fins at the hotterv cylinderportions than at the cooler portions.

6. In an air cooling arrangement ior internal combustion enginecylinders, the combination with an engine cylinder of a plurality ofannular cooling ns spaced around the cylinder wall, and dimensioned inrelative height proportional to the relative amounts of heat developedin the diil'erent cylinder portions adjacent to the several fins, meansfor supplying cooling air to said cylinder, and a jacket surroundingsaid ilns to form ducts with said fins, said jacket having axiallyextending air ports on diametrically opposite cylinder sides, one ofsaid ports being V- shaped, having its wider portion near the cylinderhead, so as to permit correspondingly larger amounts of air to enter theducts at the hotter cylinder portions than at the cooler portions, and astream line shaped cowl completely surrounding but spaced from saidjacket and said cylinder and being divided to form two chambers locatedat diametrically oppositecylinder sides, each chamber enveloping one oisaid cooling air ports, a main cooling air supply duct and a cylinderscavenging air duct disposed in one of said chambers, means at the otherchamber for discharging the cooling air, and an exhaust gas ldischargeduct arranged on the cylinder adjacent to said last-named chamber.Y

`'7. In an air cooling arrangement for internal combustion enginecylinders, the combination with an engine cylinderof a plurality oiannular cooling ilns spaced around the cylinder wall, and transversecooling flnsspaced across the cylinder head and extending in the owdirection of the cooling air to be supplied, all of said ilns beingdimensioned in relative height proportional to the relative amounts ofheat developed in the differentl cylinder portions adjacent to theseveral fins, means for supplying cooling air to said cylinder and ajacket surrounding said iins to form ducts with said ns, said jackethaving axially extending air ports on diametrically opposite cylindersides, one of said ports being V- shaped, having its wider portion nearthe cylinder head and being enlarged opposite the cylinder head into asubstantially rectangular shape, whereby larger amounts of air areindividually permitted to pass between the fins at the hotter cylinderportions than at the cooler portions,and a stream line shaped cowlcompletely surrounding but spaced from said jacket and being divided toform two chambers located at diametrically opposite cylinder sides, eachchamberen'- veloping one of said cooling air ports, a main cooling airsupply duct and a cylinder scavenging air duct disposed in one of saidchambers, means at the other chamber for discharging the cooling air,and an exhaust gas discharge duct arranged on the cylinder adjacent tosaid last-named chamber.

8. In an air cooling arrangement for internal combustion enginecylinders, the combination with an engine cylinder of a plurality ofannular cooling ns spaced around the cylinder wall, and dimensioned inrelative height proportional to the relative amounts of heat developedin the diierent cylinder portions adjacent to the several iins, meansfor supplying cooling air to said cylinder, and a jacket surroundingsaid ilns to form ducts with said fins, said jacket having axiallyextending air ports on diametrically opposite cylinder sides, one ofsaid ports being V-shaped,

having its wider portion near the cylinder head.

so as to permit correspondingly larger amounts` line shaped cowlcompletely surrounding but spaced from said jacket and said cylinder andbeing divided to form two chambers located at diametrically oppositecylinder sides, each chamber enveloping one of saidcooling air ports, amain cooling air supply duct and a cylinder scavenging air duct disposedin `one of said chambers, means at the other chamber for discharging thecooling air, and an exhaust gas discharge duct arranged on the cylinderadjacent to' said lastnamed chamber, said cooling and`scavenging airducts being integral with the cowl portion torming the appertainingchamber.

9. In an air cooling arrangement for internal combustion enginecylinders, the combination with an enginecylinder of a plurality ofannular cooling ns spaced around the cylinder wall, and dimensioned inrelative height proportional to the relative amounts of heat developedin the different cylinder portions adjacent to the several ns, means forsupplying cooling air to said cylinder, and a jacket surrounding saidfins to form ducts with said ns, said jacket having axially extendingair ports on diametrically opposite cylinder sides, one of said portsbeing V-shaped, having its wider portion near the cylinder head, so asto permit correspondingly larger amounts of air vto enter the ducts atthe hotter cylinder portions than at the cooler portions, and a streamline shaped cowl completely surrounding but spaced from 'said jacket andsaid cylinder and being divided to form two chambers located atdiametrically opposite cylinder sides, each cham- .ber enveloping one ofsaid cooling air ports, a main cooling air supply duct and a cylinderscavenging air duct disposed in one of said chambers, means at the otherchamber for discharging the cooling air, and an exhaust gas dischargeduct arranged on the cylinder adjacent to said last-named chamber, saidcooling and scavenging air ducts being integral with the cowl portionforming the appertaining chamber, and means for attaching said dividedcowl to said cylinder. j

10. In an air cooling arrangement for internal combustion enginecylinders, the combination with an engine cylinder of a plurality ofannular cooling ilns spaced around the cylinder wall, and dimensioned inrelative height r`proportional to the relative amounts of heat developedin the diierent cylinder portions adjacent to the several ns, means forsupplying cooling air to said cylinder, and a jacket surrounding saidilns to form ducts with said fins, said jacket having axially extendingair ports on diametrically opposite cylinder sides, one of said portsbeing V-shaped, having its wider portion near the cylinder head, so asto permit correspondingly larger amounts of air to enter the ducts atthe hotter cylinder portions than at the cooler portions, and a streamline shaped cowl completely surrounding but spaced from said jacket andsaid cylinder and being divided to form two chambers located atdiametrically opposite cylinder sides, each chamber enveloping one ofsaid cooling air ports, a main cooling air supply duct and a cylinderscavenging air duct disposed in one of said chambers, means at the otherchamber for discharging the cooling air, and an exhaust gas dischargeduct arranged on the cylinder. adjacent to said lastnamed chamber, saidcooling and scavenging air ducts being integral with the cowl portionforming the appertaining chamber, and means for attaching said dividedcowl to said cylinder, said two cowl portions having removable wallportions near the cylinder head to permit the attachment and detachmentof cylinder accessories.

FRITZ GOSSLAU. JOHANNES LUSZNAT.

